A new contingent of US Marines are headed to Darwin in the eighth rotation of American troops training down under.
The ramp-up from 1700 Marines expected to arrive this year to 2500 will be the first time US troop numbers reach the full planned complement.
The Morrison government says the increased US military presence was the result of Australia's strong alliance and friendship with the US.
The expansion of troop numbers was great news for the Northern Territory's businesses as well as regional security, Prime Minister Scott Morrison said in a statement issued jointly issued with Defence Minister Christopher Pyne and his intended successor Linda Reynolds on Wednesday.
"The US force posture initiatives have already proved to be a boon for local Territory businesses who have supported the rotations or been involved in part of the $2 billion being invested by Australia and the United States in infrastructure and facilities to support the initiatives," the statement said.
The first rotation of 250 Marines arrived in Darwin in 2012.
They trained for six-month periods in Australia's top end during the dry season and helped their ADF counterparts with recovery efforts after tropical cyclone Marcus hit Darwin and Palmerston in 2018.
This year, the Marines will participate in multiple training activities with Australian troops, including a new humanitarian assistance and disaster response segment.
When then-president Barack Obama announced the US base in Darwin during his visit to Australia in 2011, it was originally planned the rotations would reach a full 2500-strong air-ground taskforce by 2016.
